Ostracode is so universal in nature, the basis of all biological chains, that it deserves a little more consideration. From prehistoric times, they are found in incredible amounts in sediments around the world, and scientists are using them to date the rocks in which they are fossilized. They exist in thousands of species, have preceded us and will outlive everyone. Unlike daphnia, most do not or very little swim. They are swarming at the bottom. They are in reality, like the daphnia, very small shrimp dressed in an enveloping shell in two halves (bi-valves), whose small legs barely protrude. They grow up molting, and their calcium-rich molts are a delight for shrimp, snails and other aquatic critters. Most importantly, ostracods are the basic all-terrain scavenger. If we have known for a long time that “cleaner fish” do not exist, we discover with ostracode a tireless cleaner-gravedigger, a kind of aquatic ant, present on all occasions and eliminating the slightest waste in a minimum. of time. All dead tissue is crumbling under their number and is cleaned up in record time. Like snails and daphnids, ostracods also tend to lower water hardness over the long term by capturing calcium. Finally, ostracods, edible for fish but not very appetizing because they are a little tough, represent a living reserve food like no other species. Where a distribution of daphnia is eradicated by fish within hours, ostracods are generally shunned. They thus reach the ground and settle there. It is only during the small hunger pangs, for example when you go on vacation, that the fish will resolve to nibble them. No more hideous “vacation blocks” in commerce, and hello permanent living food!